Baling press



A118. 1940- e. w. LANGFORD n AL 2,210,591

BALING PRESS Filed lay 5, 1937 2 Sheets-Sheet 1 FIG.2.

llll IIHH HIIIIIH IIHUHH HHHHI HHH INVENTORS GEORGE W.LANGFORD BY ALFORDc. BARROWS W Away/J15 ATTORNEYS g- 1940. G. w. LANGFORD El AL 2 0, 1

BALING PRESS Filed May 5, 1937 2 Sheets-Sheet 2 FIG.3.

NORMALLY CLOSED LIMIT SWITCH Patented Aug. 6, 1940 STATES Tsar BALINGPRESS Application May 5,1937, Serial No. 140,933

4 Claims.

Figure 3 is a diagram of the electric circuitsj Figure, 4 is anelevation of the brake for looking the mechanism from operation;

Figure 5 is a diagram showing the characteristic curves of the specialmotor as compared with a standard motor.

Baling presses are used for various purposes, among which are thecompacting of loose material, such for instance as paper scraps, papercartons, etc., into a dense mass; also, the compacting of cotton andother fibrous material. In the performance of this work, the initialmovement of the platen or compression plunger meets with very littleresistance, but the load progressively builds up until for the finalcompression an exceedingly high pressure is required. Furthermore, tosecure the greatest efficiency, the speed of operation should beprogressively decreased. This is for the reason that a very largeportion of the lead is due to the compression of air trapped in theinterstices and which must be permitted to escape prior to the finalcompression. It is also desirable to perform the total operation in asshort a time as possible, consistent with the expenditure of areasonable amount of power. In view of these conditionsan idealoperation would be one in which the platen or compression plunger isinitially moved at a relatively high velocity with a relatively smallexpenditure of energy and is progressively deceler ated with increasedpower in accordance with increase in load. Various constructions havebeen devised to more or less approximate such operation, but suchconstructions involve complication in the mechanism. Also, it has beenconsidered necessary to employ an irreversible mechanism, such as a wormgearing, for moving the platen so that the load will be held when thepower is released. This involves high frictional losses andproportionally increases the power required for the operation of themachine.

With our invention we have accomplished thev desired result by anexceedingly simple construction and'one in which the frictional lossesare reduced to the minimum. Essentially, this improved constructioncomprises an electric motor having an exceedingly large range ofvariation in speed and power with the characteristic of very low torqueand low consumption of energy at high speed, and progressivelydecreasing speed and increasing torque in proportion to increase inload. While it is true that most electric motors have thischaracteristic, to some extent, for the purpose of our invention it isnecessary to have a large range, as for example a variation in speedfrom 1800 R. P. M. to under 400 R. P. M.; a variation in torque fromzero at high speed to 100 foot pounds at zero speed; and a variation incurrent consumption at 220 volts of from 6 amperes to amperes. Anotherfeature of our improvement is that we have dispensed with anirreversible transmission intermediate the motor and platen actuatingmeans, and also avoid the use of a variable speed transmission or othercomplication. In place of these, we employ a simple step-down gearingwhich operates with very low frictional losses. A third feature of ourimprovement is the automatic arresting of movement at some predeterminedload by automatically ole-energizing the motor. feature is the holdingof the mechanism from reverse movement by the automatic andinstantaneous locking of the same whenever the electric motor isole-energized.

As our improvements are applicable to various types of baling presses wedeemed it unnecessary to illustrate the construction further than themovable platen and the mechanism for actuating the same. i

As shown in Figures 1 and 2, A is the movable platen which is drawnupward in the compression chamber (not shown), by means of chains Bpassing over sprocket Wheels 0 upon aligned driven shafts D and D. Theseshafts are actuated from the motor E through the medium of a step-downreversible driving train including reduction gears inclosed within ahousing F for operating a pinion G which is in mesh with a large gear1-]: upon a shaft I. On this shaft are pinions J and J whichrespectively intermesh with gear wheels K and K upon the shafts D and D.The shaft E of the motor E extends outward from the end opposite thetransmission F into operative relation with an automatic brake L whichas hereinafter described will lock said shaft from movement whenever themotor is deenergized. 3

Still another The motor E has the characteristics above referred to andits controlling circuits are illustrated in the diagram, Figure 3, asfollows:

The motor is preferably of the multi-phase type and as shown is athree-phase motor. I, 2 and 3 are the leads extending to a reversingswitch M. This switch is manually controlled by pushbutton switches 4, 5and 6, and is automatically controlled by limit switches I and 8 and anoverload switch 9. The push-button switch 5 is nor mally opened and whenclosed starts the compression. from the lead 2 extending to the normallyclosed switch 6 and then to the switch 5. Beyond the switch 5 is aconductor II which extends to a relay l2 for closing the contacts I3, l4and 15 of the reversing switch M for driving the motor in a forwarddirection. From the relay l2 a conductor 16 extends to the limit switchI and thence through a conductor l8 to the lead 3 which completes thecircuit. The push-button switch 4 is also normally opened and whenclosed returns the movable platen to its initial position. Its circuitincludes the conductor l and normally closed switch 6. A conductor l9leading to a relay 2!! for operating the movable contacts 2|, 22 and 23of the reversing switch M to operate the motor in the reverse direction.From the relay 20 a conductor 24 extends to the limit switch 8 andthence through the conductor I 8 to the lead 3. The push-button switch 6is in multiple series with the push-button switches 4 and and includesthe circuits previously described in connection therewith. When therelay I2 is operated to close the contacts l3, l4 and i5 the leads l, 2and 3 will be connected respectively thereto through conductors 25, 26and. 21, and through conductors 28, 29 and 30 with the motor E. Theconductor 29 includes the coil 3| of the over-load switch 9. When therelay 20 is operated the closing of the contact 2! will connect the leadI with the conductor 30, through the medium of a conductor 32. Thecontact 722 will connect the lead 2 with a conductor 29 through themedium of a conductor 33 and the contact 23 will connect the lead 3 tothe'conductor 23 through the medium of a conductor 34. Thus, it will beunderstood that the press may be started in operation by the push-buttonswitch 5 and that the motor will continue to rotate in a forwarddirection until its circuit is broken, either through the operation ofthe limit switch I or the over-load switch 9. On the other hand,operation may be manually arrested at any time by the push-button switch6, and after the completion of the operation the platen can be returnedby the operation of the switch 4 which drives the motor in reversedirection until it is automatically de-energized through the operationof the limit switch 8.

As above stated, it is essential to lock the mechanism whenever themotor is de-energized so as to avoid the reverse driving of the same bythe expansive force of the compressed material. For this purpose weemploy a brake L which engages a brake drum L mounted directly upon themotor shaft extension E of the motor E. This brake must beinstantaneously released whenever the motor is energized to drive thesame either in a forward or reverse direction, and also it must beinstantaneously applied when the motor is de-energized. This as shown,we have accomplished by a solenoid L which as shown in the diagram,Figure 3, is included in shunt with the conductors 28 and 30 of themotor. This Its circuit includes a conductor l0 coil is, thereforeenergized whenever the motor circuit is closed and is de-energized uponthe opening of such circuit. As specifically illustrated, the brake hasa pair of brake shoes L and L which are connected to each other throughtoggle levers L and L, the former having an extension arm L which isconnected with a movable core L of the solenoid. The core L is normallywithdrawn by the operation of a spring L which moves the shoes towardeach other and into frictional engagement wtih the drum L. When,however, the coil L is energized which occurs simultaneously with theclosing of the motor circuit the core L will be drawn downward againstthe tension of the spring L and the shoes L and L will be separated torelease the drum L. A spring L forms a resilient element between thetoggle lever L and the shoe L and a nut L serves to adjust the tensionof said spring.

From the description above, the operation of our improved press wil beunderstood, and we have found that by eliminating the irreversibletransmission intermediate the motor and the platen operating means wecan cut down the power of the motor substantially 50%. This does notinvolve any lessening of the maximum compression pressure, or increasein time required for the complete operation. On the contrary, ourimproved construction is more expeditious in its operation for the speedis determined solely by the load. As a specific case, the totalreduction gearing between the motor and the sprocket shafts D may be aratio of 225 to 1 and because of this great reduction a comparativelysmall powered motor will furnish the maximum pressure required.Nevertheless, the high speed of operation when relieved of load or underslight load will cause a fairly rapid movement of the platen and this isretarded only to the extent that is necessary to permit the escape ofentrapped air and to furnish the necessary pressure at each point in theoperation. If desired, the press may be controlled from a more or lessremote point or, if desired, from a plurality of different points by anextension of the control circuits to such points. Thus, as indicated inFigure 3, N indicates a single point of control and the dotted lines 0and P represent two different points of control which may bealternatively used.

A motor having the characteristics above described and which wedesignate baler motor, may be designed in various ways, but thefollowing shows one specific design in comparison with a five horsepowersquirrel cage type of induction motor.

Thus it will be noted that while the frame and mechanical parts of thetwo motors are substantially the same, there is a radical differencebetween the two in electrical organization. Figure 5 shows in full linesthe characteristic torque and ampere curves of the special baler motor,and in broken lines similar curves of a standard motor, and it will benoted that whereas the standard motor attains its maximum torque at 88%of synchronous speed, the baler motor increases in torque with decreasespeed from 100% to zero. This is advantageous not only on account of theincrease in torque for final compression of the bale, but also becausethe decrease in speed gives time for the escape of entrapped air whichconstitutes a large part of the load.

What we claim as our invention is:

1. In a baling press, the combination with a compressor platen andmechanism for moving the same, of an alternating current electric motorcharacterized by a decrease in speed and increase in torque inproportion to load operable through a relatively wide range of variationof the order of from 100% to less than 25% in speed With continuoustorque increase, and a relatively low friction high constant ratiostep-down transmission between said motor and mechanism.

2, In a baling press, the combination with a compressor platen andmechanism for moving the same, of an alternating current electric motorcharacterized by a decrease in speed and increase in torque inproportion to load operable through a relatively wide range of variationof the order of from 100% to less than 25% in speed with continuoustorque increase, a reversible non-locking relatively low friction highconstant ratio step-down transmission between said motor and mechanism,and means for locking said motor from reverse movement.

3. In a baling press, the combination with a compressor platen andmechanism for moving the same, of an alternating current electric motorcharacterized by a decrease in speed and increase in torque and currentconsumption in proportion to load operable through a relatively widerange of variation of the order of from 100% to less than 25% in speedwith continuous torque increase, a relatively high constant ratioreversible non-locking step-down transmission between said motor andmechanism, an automatic cut-out for the motor circuit operated by apredetermined maximum current volume therein, a brake for automaticallylocking said motor and holding the load, and electromagnetic means forreleasing said brake in a circuit controlled by said cut-out, wherebythe opening of the motor circuit and de-energizing of the motor willinstantaneously apply said brake.

4. In a baling press, the combination with a compressor platen andmechanism for moving the same, of a high constant ratio step-downtransmission for operating said mechanism, and an alternating currentelectric motor characterized by a decrease in speed and increase intorque in proportion to load operable through a relatively wide range ofvariation of the order of from 100% to less than 25% in speed withcontinuous increase in torque, said motor being adapted to operate atmaximum speed minimum torque and minimum current consumption during theinitial movement of said platen and being responsive to increase in loaddue in part to entrapped air to decrease the speed so as to give timefor the escape of said entrapped air with a continuous increase intorque throughout the entire movement of the platen. I

GEORGE W. LANGFORD. ALFORD C. BARROWS.

